1. Field of the Invention
The present invention relates to machines for abrading a surface and, more particularly, but not by way of limitation, to machines for removing an upper layer of concrete in a road, a bridge, an airport runway or an airport taxiway.
2. Description of Related Art
Various machines have been used to remove an upper layer of a worn concrete surface in preparation for resurfacing. The familiar pneumatic hammer, or jack hammer, is one tool for concrete removal. Breaking up concrete with a jack hammer is, however, a slow and labor-intensive process. Moreover, the stress and vibration from a jack hammer may fracture or damage supporting structures.
Milling machines are also devices for concrete removal. The cutters of milling machines are rotated against the concrete to cut away the concrete. A problem with these devices is that the rotating cutters may damage or grab the metal reinforcing grid in the concrete.
Hydrodemolition may also be utilized to remove concrete. By directing jets of water under high pressure against the concrete, the concrete is eroded away. Unfortunately, the slurry created by hydrodemolition may be difficult to contain. The use of hydrodemolition on bridges makes control of the slurry even more problematic. Bridges often span rivers and streams and it is undesirable for the slurry from hydrodemolition to run into the river or stream below a bridge.